What kind of floor? Not that I have the answer,but it a place to start.I have pushed Bridgeport Mills across smooth concrete myself.Your safe mfgr may have ideas.I bet there is some cushion of air solution but I do not know what.
I wonder if it would slide easy if you laid down a flat piece of maybe 12 gage steel in the space,slid it steel on steel.Or a couple chunks of angle iron,like sliding it into a rack.Seperate them to correct width by welding a flat strip across the backside,to go against the baseboard.Could be you could get it started in on those.You would be sliding steel on steel on the outer edges of the safeIt would leave you with a small airgap under the center portion of the safe.